For a company developing a sleek and speedy aircraft, Aerion has been forced to follow a slow and twisty road. But now that Boeing has invested in the 15-year startup, its path to certifying and delivering the AS2 supersonic business jet in 2025 looks straighter and smoother.
Neither company is putting a number on Boeing’s “significant investment.” But the fact that Aerion’s new five-person board includes two senior Boeing executives makes the scale clear—one is Mike Sinnett, vice president for product strategy and future aircraft development at Boeing Commercial Airplanes.
Boeing is not the first major name to be associated with Aerion, but it may prove the most significant. The startup has courted all the main aerospace players since it was formed in 2003. It approached high-end business-jet makers Bombardier and Dassault with no success. But John Holding, who had led design of the Global Express as Bombardier’s head of engineering, joined Aerion in 2008 to lead advanced design. 
In 2014, Airbus agreed to help with design of the AS2. The assistance came from Airbus Defense and Space in Germany and helped sustain the supersonic design skills for its engineers. But Airbus completed its involvement in 2016. 
Credit: Aerion
Aerion’s biggest issue was finding a suitable engine. Its original design was conceived around a pair of Pratt & Whitney JT8D-200s, an older turbofan suited to supersonic flight because of its relatively large core and medium bypass ratio. But with introduction of the trijet AS2 in 2014, Aerion needed a quieter, cleaner, more efficient engine.
Toward the end of 2017, the company revealed it was working with General Electric to define an engine. Aerion also announced an agreement with Lockheed MartinAeronautics under which its Skunk Works would provide assistance with preliminary design. The Skunks’ civilian experience includes design of the QSST quiet supersonic business jet, which was never built, and NASA’s X-59A low-boom flight demonstrator.
All along the way, Aerion was being backed by American billionaire Robert Bass. Now the startup was paying the Skunk Works for engineering assistance while Lockheed evaluated whether to invest in the program and assemble the AS2. Aerion was also paying GE for the engine design work. 
In November 2018, GE Aviation unveiled its Affinity engine for the AS2. Designed to enable the aircraft to meet stringent Stage 5 airport noise limits yet provide supersonic cruise performance, this is an 18,000-lb.-thrust engine based on the core of the CFM56with a new two-stage fan and medium bypass ratio.
The bigger diameter of the Affinity reduced the AS2’s cruise speed to Mach 1.4, from the original 1.6. But its improved fuel efficiency increased subsonic range and enabled Aerion to offer a supersonic business jet that will be no noisier than competing subsonic aircraft entering service in the mid-2020s. 
Behind the scenes, meanwhile, Lockheed’s contract to vet the technical viability of the AS2 expired on Feb. 1, with “no plans to renew,” says the Skunk Works. “We have moved on from [that] relationship,” Aerion said, just ahead of the Boeing investment being announced. 
Under the new deal, Boeing will provide engineering, manufacturing and flight-test resources, “as well as strategic vertical content,” to accelerate aircraft design and bring the AS2 to market. The content is not specified, but Boeing’s vertical businesses include avionics, actuation, auxiliary power units (with Safran), landing gear, seats and analytics. That another Aerion board member is Ken Shaw, vice president of supply chain for Boeing Global Services, suggests the major part it plans to play in supporting the AS2. 
Boeing engineers will begin arriving at Aerion within days to participate in the preliminary design review, and the OEM’s investment will unlock a slew of key program decisions. Announcement of aerostructures and other suppliers and selection of an assembly site are expected over the course of this year, Aerion says.  
For Boeing, investment in Aerion represents an early chance to participate in a return of supersonic air travel. Since the government-funded Boeing 2707 was canceled in 1971, the company has continued to study supersonic transports, from the 300-seat transpacific High-Speed Civil Transport of the 1990s to small, low-boom airliners more recently. 
Why a supersonic business jet? In part because Boeing Business Jet operators are potential customers for a high-end aircraft like the AS2. And also because Aerion sees the aircraft as a technology platform, with larger versions to follow. Unique natural-laminar-flow aerodynamics allow the AS2 to cruise efficiently both supersonically at Mach 1.4 and subsonically at Mach 0.95 and may hold the key to a sustainable return of high-speed air travel.